SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6e3887dc56a9acab7e201141ba955b7b5e13fc0ada85cbbb6569cba1c1df042a' 
  AND token = 'vcshVkthXpGVloIgCcq6fCMqvCR3+r2T3BztXCXaiSE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}